Does JavaScript have an implementation of a set data structure?

Question

I'm looking for a decent implementation of a set data structure in JavaScript. It should be able to support elements that are plain JavaScript objects.

So far I only found Closure Library's structs.Set, but I don't like the fact that it modifies my data.

Answer 1

ECMAScript 6 has it

Spec: http://www.ecma-international.org/ecma-262/6.0/#sec-set-constructor

Usage: https://github.com/lukehoban/es6features#map--set--weakmap--weakset

Example:

var s = new Set() s.add("hello").add("goodbye").add("hello") s.size === 2 s.has("hello") === true 

A module that implements it for browsers without support: https://github.com/medikoo/es6-set

Answer 2

You could build a simple wrapper around the keys of a hash table provided by my jshashtable. I have one knocking around somewhere that I will dig out later.

UPDATE

I have completed and tested an implementation of HashSet and uploaded it to the jshashtable project on GitHub. You can download it or view the source.

var s = new HashSet(); var o1 = {name: "One"}, o2 = {name: "Two"}; s.add(o1); s.add(o2); s.values(); // Array containing o1 and o2